The Tunisian revolution in January is often cited as an inspiration for Egypt's uprising and certainly played a role in galvanising popular sentiments. But the antecedents of the current groundswell in popular anger against Mubarak first emerged after the death of Khaled Said last June. In many ways Said's murder is a metaphor for the entire crisis.

Said visited an internet café near his flat in the coastal city of Alexandria where local policemen were sharing a video among themselves which showed them illegally taking seized drugs and money. The file was accidently transferred to Said's computer over a wireless network and he was detained after forwarding it to friends. Witnesses subsequently reported seeing policemen kick and smash his head against marble tables and into staircases in broad daylight.

An official government report said his death was caused by a drugs overdose. Said's unconvinced relatives bribed a mortuary worker to take photos of his corpse which revealed all the indelible horrors of state- sanctioned torture: a cracked skull and twisted, rigor mortis features.

Wael Ghonim, Google's Middle East marketing manager, ensured the pictures went viral after creating the page "We are all Khaled Said" on the social networking site Facebook. Egypt's savvy internet generation finally found an emblem to rally their anger, just as the dying images of Neda Soltan had galvanised Iranians during the Green movement protests in 2009.

Ghonim would come to epitomise the spirit of the uprising. He left the safety of Dubai, where he worked, to join the protests in Cairo and was arrested on January 27. During 12 days in police custody, he was blindfolded, kept in solitary confinement and threatened with torture. Ghonim was released on February 7, and quickly became the public face of what had otherwise been a leaderless revolt.

Facebook may have spurred Egypt's affluent youth into action, but the protesters occupying Tahrir Square represented all walks of life: the rural poor, the elderly, the upwardly-mobile middle classes, Christians and Muslims. The real strength of new media has been its ability to provide a platform for previously disparate groups to come together and decide on coordinated action. The people involved were not necessarily new, but groups like Ghonim's were suddenly in touch with members of the "April 6 Youth Movement" founded in 2008 in response to industrial disputes in El-Mahalla El-Kubra, a large industrial town nestled on the Nile Delta. Yet it is easy to overstate the role of social networking sites. When the government suspended mobile phone and internet access following the Friday "day of rage", thereby smothering the role of Facebook and Twitter, protesters responded by mobilising more than a million people across Egypt the following Tuesday.

In this way, the protesters proved themselves to be resilient and capable of evolving in response to Mubarak's intransigence. Their ability to assemble a broad cross-section of society despite government clampdowns made the movement almost impossible to understand. When I asked protesters in the square about it, they simply replied, "No one has organised this, the people have done it." It is hard to be sure who drove the revolution forward, or how mass rallies could be repeatedly staged without some kind of obvious leadership. Even Egypt's political leaders seemed bemused.